I am having a real devil of a time getting a vice for bench breaking a master cylinder, my question is Can you bench break a master cylinder in the engine bay in place of the old broken master cylinder?..but not hook it up to the actual brake lines and but instead run hoses to a mini-bucket filled with brake fluid?...now keep it in mind I have NO MONEY and just the master cylinder , brake fluid and new padz!!!

thanks in advance!!!

 

you can bleed the master cylinder on the car instead of in a vice. The bleeder kits work well to jun the rubber hoses into the cylinder reservoir and just slowly cycle down the pedal to bleed the air out of the master cylinder piston chamber. You will stil need to bleed the lines starting at the rh rear and working your way towards the master cylinder. Just dont run the cylinder dry or allow the tubes coming off to suck air when you release on the plunger.

 

Cool, were gonna install new padz and nomatter what we will re-bleed the brakes too!

thankz for that!

 

Welp!...I replaced the brake master cylinder, swapped the brake pads, bled them twice!*...No luck at all!...bleeding with the car off it gets good pressure, then when I start it up , there is no more pressure, I pumped them and I can clearly see air bubbles!...W.T.F.?...so we bled from the master cylinder too , both front and rear lines!...So Am I missing something?...If I was not broke (moneywise), I would take it to a shop to have the problem corrected, is it possible the brake booster is shot?...inside the car I get a loud hissing noise when ever I pump the brakes!

 

No you CANNOT bleed it on the car and expect it to work.

Problem is, the lines ARE NOT connected to the actual cyl, at their highest point. Therefore, you can bleed them for an hour every day from now till Doomsday, and twice every Sunday just for good measure, and NEVER get the air out of there, because there will ALWAYS be a bubble of air trapped up above the ONLY place it can "exit", namely, the line fitting.

You gotta hold the MC level while bleeding, so that the line fitting is at the highest point (where the air goes to). Simple as that. Not rocket science here, just a car. Hardly even 9th grade science (for those who paid attention in that class).

 

And on the subject of the noise, if it just kind of goes "spooosssssshhhhhhhhh" while you're pushing the brakes and then quits when the pedal stops moving, then most likely, no prob; if it keeps on hissing, then yes you need a booster.

It doesn't care about "broke". No point in P&Ming about that on here. Either you want to fix it, or you don't; simple as that.

It's ALL simple.

 

Napa sells master cylinder bench bleeding kit that worked well for me when I did my Blazer. It took me longer to drive to Napa to get the kit then it did to actually bleed them in a vise. Napa sells both metric and SAE. I think the metric ones are blue and the SAE ones are red. I bought both and I think I used the red ones but I could be wrong as it was a while ago.

Also, 99.99% of all aftermarket master cylinders are JUNK right out of the box. I went through 2 of them and gave up and went to a bone yard and bought a used OEM one and it worked perfect. Just an FYI.

 

The nes M/C has been bench broke and we bled the brakes at the calipers and now just below the M/C...what am I missing???...B.T.W> I get multiple bubbles in the M/C when pumping!

 

If the master has been properly bled AND is working correctly then your next step will be bleeding at the calipers like you mentioned. If you are still getting air in the system then you may have a leak somewhere else. maybe at one of the lines on the master or somewhere else in the system. I went through this with my Blazer and it pissed me off until I found out that I ruptured a brake line going to the LF wheel from constantly trying to pump the brakes to bleed them.

You dont have ABS so the process of bleeding your car is very simple assuming all parts are working correctly and there is no leaks anywhere.

Remember though, I went through 2 NEW master cylinder from Dorman and they were both bad out of the box. I put a used master back in my truck and it worked perfect and my brakes bled perfect.

 

Do not crack open the lines at the master cylinder after you have bled the calipers. Otherwise you will have to start all over.

 

it aint rocket surgery..
you need a vise to bench bleed the master cylinder.. simple as that.
clamp the master cylinder in the vise with the piston perfectly level. put the bench bleeding lines on- they just loop from the ports up into the fluid reservoir.. fill the reservoir with fluid, making sure to keep the ends of the lines below the fluid level unless you like the idea of brake fluid splattering everywhere..

now comes the important part- use a large philips screwdriver to s-l-o-w-l-y push the piston in about an inch.. you don't want to bottom it out.. the fluid level will go down after the first pump- top it off. keep s-l-o-w-l-y pumping the piston in and out and topping off the fluid until there are no air bubbles coming out of the lines.. it might take a minute, it might take 10 minutes.. if you keep getting air bubbles for longer than that, check the piston next to where you are pushing with the screwdriver for fluid.. if it's wet, you are sucking air.. you might as well stop right there, because that master cylinder is junk and you need to take it back for another one..

once you get it bled, keep the bleeder lines installed and put it on the car, only unhooking the bleeder lines right before hooking up the lines on the car..

now you gotta bleed the brakes on the car...